From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: MIME-Version: 1.0 In-Reply-To: <201207052357.44494.rjw@sisk.pl> References: <201206281201.02414.rjw@sisk.pl> <201207052357.44494.rjw@sisk.pl> From: Bjorn Helgaas Date: Thu, 5 Jul 2012 16:31:17 -0600 Message-ID: Subject: Re: [PATCH] PCI / PM: Restore the original behavior of pci_set_power_state() To: "Rafael J. Wysocki" Cc: Jesse Barnes , Linux PM mailing list , LKML , Matthew Garrett , linux-pci , Huang Ying Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: On Thu, Jul 5, 2012 at 3:57 PM, Rafael J. Wysocki wrote: > On Thursday, July 05, 2012, Bjorn Helgaas wrote: >> On Thu, Jun 28, 2012 at 4:01 AM, Rafael J. Wysocki wrote: >> > From: Rafael J. Wysocki >> > >> > Commit cc2893b6 (PCI: Ensure we re-enable devices on resume) >> > addressed the problem with USB not being powered after resume on >> > recent Lenovo machines, but it did that in a suboptimal way. >> > Namely, it should have changed the relevant code paths only, >> > which are pci_pm_resume_noirq() and pci_pm_restore_noirq() supposed >> > to restore the device's power and standard configuration registers >> > after system resume from suspend or hibernation. Instead, however, >> > it modified pci_set_power_state() which is executed in several >> > other situations too. That resulted in some undesirable effects, >> > like attempting to change a device's power state in the same way >> > multiple times in a row (up to as many as 4 times in a row in the >> > snd_hda_intel driver). >> > >> > Fix the bug addressed by commit cc2893b6 in an alternative way, >> > by forcibly powering up all devices in pci_pm_default_resume_early(), >> > which is called by pci_pm_resume_noirq() and pci_pm_restore_noirq() >> > to restore the device's power and standard configuration registers, >> > and modifying pci_pm_runtime_resume() to avoid the forcible power-up >> > if not necessary. Then, revert the changes made by commit cc2893b6 >> > to make the confusion introduced by it go away. >> > >> > Signed-off-by: Rafael J. Wysocki >> > --- >> > drivers/pci/pci-driver.c | 14 ++++++++------ >> > drivers/pci/pci.c | 19 ++++++++++++++++++- >> > drivers/pci/pci.h | 1 + >> > 3 files changed, 27 insertions(+), 7 deletions(-) >> > >> > Index: linux/drivers/pci/pci.c >> > =================================================================== >> > --- linux.orig/drivers/pci/pci.c >> > +++ linux/drivers/pci/pci.c >> > @@ -662,6 +662,19 @@ void pci_update_current_state(struct pci >> > } >> > >> > /** >> > + * pci_power_up - Put the given device into D0 forcibly >> > + * @dev: PCI device to power up >> > + */ >> > +void pci_power_up(struct pci_dev *dev) >> > +{ >> > + if (platform_pci_power_manageable(dev)) >> > + platform_pci_set_power_state(dev, PCI_D0); >> > + >> > + pci_raw_set_power_state(dev, PCI_D0); >> > + pci_update_current_state(dev, PCI_D0); >> > +} >> > + >> > +/** >> > * pci_platform_power_transition - Use platform to change device power state >> > * @dev: PCI device to handle. >> > * @state: State to put the device into. >> > @@ -707,7 +720,7 @@ static void __pci_start_power_transition >> > */ >> > int __pci_complete_power_transition(struct pci_dev *dev, pci_power_t state) >> > { >> > - return state >= PCI_D0 ? >> > + return state > PCI_D0 ? >> > pci_platform_power_transition(dev, state) : -EINVAL; >> >> This hunk conflicted with Huang's D3_COLD patches. I fixed it up; can >> you check and make sure I did it correctly? >> >> I pushed the resolution to here: >> git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git on the >> pci/rafael-pci_set_power_state-rebase branch. > > Yes, it looks good. The point is to make __pci_complete_power_transition() > return the error code for PCI_DO too. Applied to my "next" branch and pushed, thanks a lot! Bjorn